Grounding arrangement for highfrequency transfer switches



March; 6, 1951' A. PROCTOR 2,543,804 GROUNDING ARRANGEMENT FOR HIGH-FREQUENCY TRANSFER SWITCHES Fi led Aug. 20, 1947 3 Sheets-Sheet 1 Tiqln INVENTOR A 05 T/A/ p906 70/? BY ATTO R N EYS March 1951 r A. PROCTOR GROUNDING ARRANGEMENT FOR HIGH-FREQUENCY TRANSFER SWITCHES Filed Aug. 20, 1947 s Sheets-Sheet s Fig.3.

lNVENTOR #(UT/A/ PRQCTQR BY ATTORNEYS Patented Mar. 6, 1951 GROUNDING ARRANGEMENT FOR HIGH- FREQUENCY TRANSFER SWITCHES Austin Proctor, Louisville,'Ky., assignor to The Girdler Corporation, Louisville, Ky., a corporation of Delaware Application August 20, 1947, Serial No.-769,660

This invention relates to an improved grounding arrangement for high-frequency switches of the type particularly applicable for use with high-frequency systems and has for an object the provision of a grounding arrangement by means of which every one of a plurality of stationary contacts will be automatically connected to ground except during final movement of a movable contact into contact-engagement with a selected stationary contact.

As explained in Zottu Patent No. 2,419,307, a transfer switch is necessary if a high frequency generator is to be utilized to supply energy, first, to one load, and then to other selected loads for the reason that the large size of conductors required for the transmission lines makes difficult, if not impractical, the connection and disconnection of one load to the other. The transfer switch of the Zottu patent includes a reasonably satisfactory means for rounding all of the stationary contacts other than the one selected by an operator, but leaves something to be desired in that none of the stationary contacts is connected to ground during transfer of the movable contact from one circuit-controlling position to another, a situation which is to be avoided.

In carrying out the present invention, in one form thereof, a grounding arrangement is provided which automatically operates to maintain each of a plurality of stationary contacts at ground potential and in which all stationary contacts are connected to ground during all movements of a movable contact from one stationary contact to another. More particularly, the grounding arrangement automatically operates not only to ground each stationary contact, but also the inner and outer conductors of associated concentric lines and to maintain them at ground potential until the final movement of a movable contact into a selected circuit-controlling position.

For further objects and advantagesof the invention, reference is to be had to the following description and to the accompanying drawings in which the invention has been illustrated as applied to a transfer switch which forms the subject matter of an Ellsworth and Gilbert patent application, co-workers of mine, filed August 20, 1947, Serial No. 769,698.

In the drawings:

Fig. 1 is a fractional view of a switch embodying the invention with the operating handle in open position;

Fig. 2 is a plan view of the switch with the operating handle in closed position; and

7 Claims. 01. 200-4 Fig. 3 is a plan view of the grounding arms in their retracted positions.

Referring to he drawings, the invention in one form has been shown as applied to a transfer switch comprising a movable contact l0 secured to a flexible conductor l I and pivotally supported on an arm I2 extending from a bracket M. The bracket l4 forms a part of an operating mechanism including three insulators [5, I6 and I! which are connected to a bracket l3'which is, in turn, secured to a rod l9 slidably mounted in bearings 20 and 2 I. A toggle, includin a toggle link 22 and an operating handle and lever 23, serves to move the movable contact I 0 toward and away from a cooperating stationary contact 24. Additional stationary contacts 25, 26 and 21 may be seen in Fig. 2, though, of course, a greater number of stationary contacts may be utilized. The operating mechanism, including the bearings 20 and 2|, are supported on a turntable or subframe 30 which is pivotally carried by a bracket 28 resting upon a base 29.

As shown, the switch is in an open circuit position with the movable contact In ready for movement into engagement with the stationary contact 24. It is to be observed that the conductor 32, to which the stationary contact 24 is secured, forms the inner conductor of a concentric transmission line, the outer grounded conductor 33 of which is bolted to or otherwise suitably secured to the housing 34 of the transfer switch. With the parts in their illustrated positions, it is to be observed that the inner conductor 32 is connected to the outer grounded conductor 33 of the con centric or coaxial line by means of contact arms -36 and 31, Fig. 3. Though one arm would be enough to complete the aforesaid rounding connection, the use of two arms afiords double protection in the establishment of a good grounding circuit at each stationary contact. As shown in Fig. 1, the contact arm 36 is pivoted at 38 on a bracket 39, the lower end of arm 36 being pivoted by a pin 40 to the vertically slotted end of a turn buckle 4| secured to the end of a rod 42. The rod 42 is supported in bearing members 44, 45 and 46 for slidable movement and is biased by means of a spring 48 acting on a collar 49 secured to the rod 42 for maintaining the contact arms 36 and 31 in their illustrated positions. Each of contact arms 36 and 3! includes two sets of inwardly extending resilient contact fingers 50 and 5|. These slidably and wipingly engage the inner conductor 32. Each of contact arms 36 and 31 also includes resilient contact members 52 and 5 3 which, it will be observed, Fig, 1, are riveted to the contact arm at one end thereof, the opposite end being free to provide wiping and sliding contact engagement with a circular ring 54 connected to and forming a part of the housing, as well as of the outer conductor 33 of the associated concentric line. Thus, with the parts in the positions shown, the housing of the switch, the outer conductor which is grounded, and the inner conductor are all connected together and all remain at ground potential until the arms 36 and 31 have been moved out of the circuitclosing positions.

The actuating lever 55 for arms 36 and 31 is pivoted to the subframe 36 as at 56 and is attached to a link 51 extending from the bracket is. Each of the actuating rods 42, one for each stationary contact, has one end disposed for engagement by the actuating lever 55. Accordingly, when the operating handle 23 is moved downwardly about its pivotal support 58, the toggle is straightened, the rod [9 and the bracket l8 move toward the stationary-contact to rotate the lever 55 into engagement with the end of the actuating rod 42. This rod acting upon the lower end of the grounding switch member 36 rotates it about its pivot 38 in a counterclockwise direction and out of its circuit-closing position. When the movable contact l6 has been moved into engagement with the stationary contact 24, the grounding arms 36 and 3'! will extend substantially horizontally from their ivotal sup port and well awa from the contacts l6 and 24. Thus, it will be seen that the stationary contact 24, the housing 3d of the switch and the grounded outer conductor of the coaxial line will all be connected together until the movable contact In has been moved substantially into its circuitclosing position with respect to stationar contact 24.

The foregoing arrangement is deemed highly desirable since the switch may be operated from the position illustrated in Fig. 1 for engagement with any selected one of stationary contacts 24 to 27. During such movement, as. for example, from indexing slot 10 to indexing slots H, 12 or 13, Fig. 2,, it is desirable that all stationary contacts then be at ground potential and this is accomplished regardless of the wishes of the operator. It is fail-safe.

With each of stationary contacts 25, 26 and 2! supported from inner conductors of coaxial or concentric lines 6|, 62 and 63 are associated arms 36a and 31a, which are structurally and operationally identical with the arms 36 and 31. Accordingly, when the movable contact engages the stationary contact 2 i, the remaining grounding arms 36a and 31a connect to ground the housing 3 3 and they connect each of the inner conductors of the respective coaxial lines to the outer grounded conductors 64, 65 and 66 thereof. In Fig. 2 the parts have been illustrated with the operating handle 23 in the closed circuit position with the movable contact pressed into engagement with the stationary contact 24, and of course with the arms 35 and 3'! moved out of their grounding positions as, for example, rotated about pivot 38 to substantially horizontal positions.

While a preferred embodiment of the invention has been described, it will be understood that modifications may be made therein within the scope of the appended claims.

What is claimed is:

l. A. transfer switch having a plurality of stationar contacts and a rotatable contact selectively movable into and out of engagement respectively with a selected one of said stationary contacts, at least one grounding arm for each stationary contact, pivotal mounting means for said arm, biasing means normally holding said arm in position to connect its associated stationary contact to ground, and actuating structure including a reciprocative member for moving said rotatable contact into engagement with a selected stationary contact and for rotating the associated one of said grounding arms out of grounding position with respect to said selected stationary contact while leaving all other of said grounding arms connected for grounding their respective stationary contacts, and for again grounding said selected contact before rotation of said rotatable contact toward another stationary contact.

2. The combination set forth in claim 1 in which each stationary contact forms an extension of the inner conductor of a concentric line and in which the outer conductor of said concentric line is grounded, each. grounding arm having contacts for engaging and completing connections between said inner and outer conductors of said concentric line.

3. A transfer switch having a plurality of stationary contacts and a rotatable contact selectively movable into and out of engagement respectively with a selected one of said stationary contacts, at least one grounding arm for each stationary contact, means pivotally supporting each grounding arm for rotation into and out of grounding position with its associated stationary contact independently of each other grounding arm, means including a reciprocative actuating rod for biasing each grounding arm to its circuitclosing position, actuating mechanism selectively operable to move said rotatable contact into and out of circuit-closing position with a selected one of said stationary contacts, and means forming a driving connection between said actuating mechanism and said actuating rod for rotating said grounding arm associated with the selected stationary contact from its circuit-closing position to a circuit-opening position, thereby to remove said grounding connection as the rotatable contact is being moved towards its circuit-closing position.

4. The combination set forth in claim 3 in which each stationary contact is supported from the inner conductor of a concentric line and in which the outer conductor thereof is connected to ground, and in which two grounding arms for each stationary contact are respectively provided with resilient contact members for interconnecting the inner and outer conductors of each concentric line.

5. The combination set forth in claim 3 in which each stationary contact is supported on a conductor extending through an opening formed in the housing of the switch and in which each of said grounding arms includes resilient contact members for interconnecting said inwardly ex tending conductor and the housing of said switch.

6. A transfer switch having at least one stationary contact and a movable contact operable into. and out of engagement with said stationary contact, actuating mechanism for said movable contact including a rod connected to said movable contact and slidably mounted for moving said movable contact toward and away from said stationary contact, an electrically conductin grounding arm for said stationary contact, a pivotal support for said arm disposed in spaced relation with respect to said stationary contact, a rod engaging one end of said arm and slidably mounted for rotating said arm out of grounding position with said stationary contact, means operable by said actuating mechanism for engaging said last-named rod to rotate said arm out of grounding engagement with said stationary contact as said movable contact is moved toward and into engagement with said stationary contact, said arm having spaced contact structures carried thereby, one for electrically engaging said stationary contact and the other for completing an electrical connection to ground said stationary contact when said arm is in said grounding position, and resilient means operable upon movement of said movable contact away from said stationary contact for moving and biasing said arm to said grounding position.

7. A transfer switch for high voltage high-frequency electrical energy having a plurality of stationary contacts and a rotatable contact selectively movable into and out of engagement respectively with a selected one of said stationary contacts, at least one grounding arm for each stationary contact, pivotal mounting means for said arm, biasing means including a reciprocative member associated with each stationary'contact for normally holding said arm in position to connect its associated stationary contact to ground, indexing means for aligning said rotatable contact with a selected stationary contact, said indexing means having an index station for each said stationary contact, and actuating structure including leverage structure and a reciprocative rod for moving said rotatable contact into engagement with said selected stationary contact and for operating the associated one of said reciprocative members to rotate the associated one of said grounding arms out of grounding position with respect to said selected stationary contact while leaving all other of said grounding arms connected for grounding their respective stationary contacts, and for again grounding said selected stationary contact upon disengagement of said rotatable contact before rotation of the latter to another indexing station for engagement with another stationary contact.

AUSTIN'PROCTOR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 983,380 Lord Feb. 7, 1911 1,515,578 Glaser Nov. 11, 1924 2,277,555 Meuer Mar. 24, 1942 2,337,130 Rubel Dec. 21, 1943 2,419,307 Zottu Apr. 22, 1947 2,427,940 Ayres Sept. 23, 1947 

